package cn.chiship.framework.common.config.filter;

import cn.chiship.sdk.core.util.StringUtil;
import cn.chiship.sdk.core.util.html.EscapeUtil;
import org.apache.commons.io.IOUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;

/**
 * XSS过滤处理
 *
 * @author lijian
 */
public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {

	/**
	 * @param request
	 */
	public XssHttpServletRequestWrapper(HttpServletRequest request) {
		super(request);
	}

	@Override
	public String[] getParameterValues(String name) {
		String[] values = super.getParameterValues(name);
		if (values != null) {
			int length = values.length;
			String[] escapseValues = new String[length];
			for (int i = 0; i < length; i++) {
				// 防xss攻击和过滤前后空格
				escapseValues[i] = EscapeUtil.clean(values[i]).trim();
			}
			return escapseValues;
		}
		return super.getParameterValues(name);
	}

	@Override
	public ServletInputStream getInputStream() throws IOException {
		if (!isJsonRequest()) {
			return super.getInputStream();
		}

		// 为空，直接返回
		String json = IOUtils.toString(super.getInputStream(), StandardCharsets.UTF_8);
		if (StringUtil.isNullOrEmpty(json)) {
			return super.getInputStream();
		}

		// xss过滤
		json = EscapeUtil.clean(json).trim();
		final ByteArrayInputStream bis = new ByteArrayInputStream(json.getBytes(StandardCharsets.UTF_8));
		return new ServletInputStream() {
			@Override
			public boolean isFinished() {
				return true;
			}

			@Override
			public boolean isReady() {
				return true;
			}

			@Override
			public void setReadListener(ReadListener readListener) {
			}

			@Override
			public int read() throws IOException {
				return bis.read();
			}
		};
	}

	/**
	 * 是否是Json请求
	 */
	public boolean isJsonRequest() {
		String header = super.getHeader(HttpHeaders.CONTENT_TYPE);
		return MediaType.APPLICATION_JSON_VALUE.equalsIgnoreCase(header);
	}

}
